This invention is concerned with a cheese hardening machine, for hardening mozzarella, scamorza, provolone and other kinds of pasta filata cheese.
Freshly molded mozzarella cheeses are, as known in the art, soft and malleable and have to be hardened by immersion in cold water for a period sufficient to completely chill their mass. Fast chilling can only be achieved if the product is kept moving with respect to the water. Moreover, individual mozzarella balls or knobs should not be crowded, so that they are not squeezed together and become misshapen. Therefore, mechanized chilling vats were first provided, where the freshly molded product is horizontally transported through cold water on a conveyor belt and is then mechanically withdrawn at the delivery end of the vat. The length of the vat and the conveyor travel speed are suitably chosen in order to obtain the required immersion time. The product thereby moves with respect to the water, it does not become crowded, and it is not scraped by sliding against the surfaces of the vat.
However, in this type of hardening machines the product lies on the conveyor belt in the same position during the entire run through the vat, so that, even if the mozzarella balls are not squeezed, they are deformed by the force of gravity acting in the same direction for the entire immersion time, while the product is still plastic, and, on the other hand, the portion of the cheese surface that is in contact with the belt is not subjected to the same chilling action as the portion of the surface that is in direct contact with the cold water. The finished product is therefore flattened and its surface is uneven in texture or color.
Moreover, with such prior chilling vats, it is difficult or impossible to reach the area of the vat underneath the belt for cleaning, unless the entire belt-supporting structure is lifted out by means of bulky and expensive mechanical gear.
Prior Italian published patent application No. 67683-A/78, filed on Mar. 28, 1978, discloses a cheese hardening vat having a set of short, overlapping conveyor belts, which cause the cheeses to roll over in passing from one belt to the next, so that the cheese is neither flattened nor unevenly chilled. Moreover, each belt-support structure in such prior chilling vat can be individually upended, so that the area beneath the belts can be easily accessed for cleaning.
Hardening vats with overlapping conveyor belts, however, are mechanically complex, because of the numerous gears and transmissions necessary to propagate motion to all the belts, and because of the separate frames and rollers required for supporting each belt. On the other hand, the problem of cleaning is not fully solved either, because it is still difficult to clean the recesses within each belt structure. Moreover, the plastic material of the belts themselves is often less than satisfactory from the point of view of hygiene.